imagemagick
Command-line powerhouse for image processing - format conversion, resizing, effects, batch operations.
When to Use
- Format conversion - PNG/JPEG/WebP/GIF between formats with quality control
- Batch processing - Resize, optimize, watermark hundreds of images at once
- Web optimization - Create responsive sizes, strip metadata, compress for web
- Effects & filters - Blur, sharpen, color adjustments, artistic effects
Key Capabilities
| Operation | Examples |
|---|---|
| Resize | Fit, fill, crop, maintain aspect, exact dimensions |
| Convert | PNG↔JPEG↔WebP with quality settings |
| Effects | Blur, sharpen, grayscale, sepia, watermarks |
| Batch | Process entire folders with mogrify or loops |
| Optimize | Strip metadata, progressive JPEGs, WebP compression |
Common Use Cases
E-commerce Product Manager
Who: Store owner with 200 product photos Prompt: “Use imagemagick to batch process product images: resize to 1000x1000 square from center, convert to WebP 85% quality, create 300x300 thumbnails”
Social Media Manager
Who: Content creator preparing Instagram posts Prompt: “Use imagemagick to create Instagram square (1080x1080) from these landscape photos, center crop, add white watermark bottom-right”
Web Developer
Who: Dev optimizing site performance Prompt: “Use imagemagick to generate responsive image set: create 320w, 640w, 1024w, 1920w versions of all JPEGs, WebP format, strip metadata”
Email Marketer
Who: Newsletter designer reducing image sizes Prompt: “Use imagemagick to optimize images for email: max width 600px, JPEG quality 75, strip all metadata, progressive encoding”
Photographer
Who: Pro photographer watermarking portfolio Prompt: “Use imagemagick to add logo watermark to all photos in folder, position bottom-right with 20px margin, 50% opacity”
Quick Reference
# Resize (maintain aspect)
magick input.jpg -resize 800x600 output.jpg
# Square crop from center
magick input.jpg -resize 1000x1000^ -gravity center -extent 1000x1000 output.jpg
# Convert format
magick input.png -quality 85 output.jpg
# Batch resize all
mogrify -resize 800x *.jpg
# Batch to different folder
mogrify -path ./output -resize 800x600 *.jpg
# Web optimize
magick input.jpg -quality 85 -strip -interlace Plane output.jpg
# Add watermark
magick input.jpg logo.png -gravity southeast -geometry +10+10 -composite output.jpg
# Grayscale
magick input.jpg -colorspace Gray output.jpg
# Create thumbnails
for f in *.jpg; do magick "$f" -thumbnail 200x200 "thumb_$f"; done
# Responsive sizes
for w in 320 640 1024 1920; do magick input.jpg -resize ${w}x out-${w}w.jpg; doneGeometry syntax:
800x600= fit within (maintains aspect)800x600!= exact size (may distort)800x600^= fill (may crop)800x= width 800, auto heightx600= height 600, auto width
Pro Tips
Quality settings:
- 95-100: Archival (large files)
- 85-90: Web publishing (recommended)
- 70-80: Email, thumbnails
- WebP: Use 80-85 for best size/quality
Batch best practices:
- Always backup originals before mogrify (modifies in-place)
- Test command on single file first
- Use
-pathto preserve originals:mogrify -path ./output ... - For complex operations, use loops instead of mogrify
Web optimization combo:
magick input.jpg -resize 1920x -quality 85 -strip -interlace Plane output.jpgNot activating? Say: “Use imagemagick skill to resize these images to 800px width and convert to WebP”
Related Skills
- FFmpeg - Video/audio processing
- Frontend Design - UI component creation
- Chrome DevTools - Browser debugging
Key Takeaway
ImageMagick = Swiss Army knife for images. One command processes hundreds of files. Essential for any workflow involving image optimization, batch conversion, or automated resizing.